Yes, that is legal. But what matters is control of the board and how the structure of the foundation is set up. With six voting board members assuming things like who is the CEO of the company is something that they are allowed to vote on (it normally would be) she could technically be out of there tomorrow. But this is politics, it is not a merit based affair and there is a fair chance that two or more of the board members are beholden to Mitchell and that would protect her from any attempt to oust her.